Mental timing studies may be influenced by powerful cognitive illusions that can produce an asymmetry in their rate of progress relative to neuronal timing studies. Both types of timing research are also governed by a temporal asymmetry, expressed by the fact that the direction of causation must follow time's arrow. Here we refresh our earlier suggestion that the temporal asymmetry offers promise as a means of timing mental activities. We update our earlier analysis of Libet's data within this framework. Then (...) we consider the surprises which often occur on those rare occasions when neural timing experiments parallel mental timing work exactly. Together, these surprises and asymmetries prescribe a relentlessly meticulous and fully transparent exposition of timing methods, terms, and concepts which shuns plausible narratives, even when buttressed by rigorous formal models, unless guided by apposite empirical evidence. (shrink)

Susan Pockett presents sound arguments supporting her reinterpretations of data that Libet and co-workers used to support a number of intriguing and influential conclusions regarding the microgenesis and timing of conscious sensory experience and volitionally controlled motor responses. The following analysis, extending and elaborating some of her main arguments, proposes that Libet's experimental methodologies and rationales, and thus also his interpretation of data, are flawed and that neglect or ignorance of methodological and empirical constraints well known to sensory psychologists risks (...) drawing premature or faulty conclusions about the timing of conscious experience. (shrink)

In recent times we have seen an explosion in the amount of attention paid to the conscious brain from scientists and philosophers alike. One message that has emerged loud and clear from scientific work is that the brain is a dynamical system whose operations unfold in time. Any theory of consciousness that is going to be physically realistic must take account of the intrinsic nature of neurons and brain activity. At the same time a long discussion on consciousness among philosophers (...) has resulted in our distinguishing several kinds of consciousness. So when we ask where the place of consciousness is in nature we may mean several different things. In this chapter I will argue that it is plausible that all of the kinds of consciousness turn out to be nothing but patterns of synchronized neural activity in various frequencies against a dynamically changing chemical background. (shrink)

It's very interesting to see neurophysiological evidence brought to bear on the puzzling question of conscious experience. Many have observed that information-processing models of cognition seem to leave consciousness untouched; it is natural to hope that turning to neurophysiology might lead us to the Holy Grail. Still, I think there are reasons to be skeptical. There are good reasons to suppose that neurophysiological investigation contributes to cognitive explanation at best in virtue of constraining the information-processing structure of cognition. Of course (...) this is a very large and significant role for it to play, but it may be over-optimistic to suppose that it can play some further explanatory role, taking us where information-processing theories cannot. If so, then neurophysiological accounts will be no more and no less successful at dealing with consciousness than information-processing accounts are. (shrink)

A remarkable hypothesis has recently been advanced by Libet and promoted by Eccles which claims that there is standardly a backwards referral of conscious experiences in time, and that this constitutes empirical evidence for the failure of identity of brain states and mental states. Libet's neurophysiological data are critically examined and are found insufficient to support the hypothesis. Additionally, it is argued that even if there is a temporal displacement phenomenon to be explained, a neurophysiological explanation is most likely.

The temporal granularity of consciousness may be far less fine than the real-time information processing mechanisms that underlie our sensitivity to small temporal differences. It is suggested that conscious time perception, like space perception, is subject to errors that belie a unitary underlying representation. E. R. Clay's concept of the “specious present,” an extended moment represented in consciousness, is suggested as an alternative to the more common notion of instantaneous experience that underlies much reasoning based on the “time of arrival” (...) in consciousness. (shrink)

Despite the fact that attention is a core property of all perceptual and cognitive operations, our understanding of its neurophysiological mechanisms is far from complete. There are many theoretical models that try to fill this gap in knowledge, though practically all of them concentrate only on either involuntary (bottom-up) or voluntarily (top-down) aspect of attention. At the same time, both aspects of attention are rather integrated in the living brain. In this chapter we attempt to conceptualise both aspects of attentional (...) state within the theory of Operational Architectonics of brain and mind functioning, which provides a plausible theoretical basis for neurophysiological understanding of how attention is brought to existence in the living brain. (shrink)

This article provides an overview of recent developments in solving the timing problem (discreteness vs. continuity) in cognitive neuroscience. Both theoretical and empirical studies have been considered, with an emphasis on the framework of Operational Architectonics (OA) of brain functioning (Fingelkurts and Fingelkurts, 2001, 2005). This framework explores the temporal structure of information flow and interarea interactions within the network of functional neuronal populations by examining topographic sharp transition processes in the scalp EEG, on the millisecond scale. We conclude, based (...) on the OA framework, that brain functioning is best conceptualized in terms of continuity-discreteness unity which is also the characteristic property of cognition. At the end we emphasize where one might productively proceed for the future research. (shrink)

Reinterpretations of Libet's results have received support from most commentaries. Libet's arguments against alternative hypotheses are contested. Latency depends on intensity. Integration of intensity and duration explains the Minimum Train Duration. Analogies of Libet's timing of intentions with control experiments indicate biases of opposite signs, according to intramodal or intermodal results. Rosenthal's view of nonconscious intentions becoming conscious after a delay is favored. Compatibilist free will is discussed.

A commentary on articles by Klein, Pockett, and Trevena and Miller, in this issue, is given. Average shift in the point of subjective equality , calculated by Klein on Libet's data, and corresponding change in mean shift, calculated by Libet et al. , may be “corrected,” taking as a reference point the end of the minimum train duration. Values obtained, if significant, indicate a latency for conscious sensation of the skin stimulus of at least 230 ms. Pockett's main conclusions are (...) favored, but her explanation of peripheral–lemniscal couplings is found to be unconvincing. Trevena and Miller's article unsuccessfully tries to rescue a dualist interactionist view. Libet's method of timing intentions is thoroughly criticized. (shrink)

1. Introduction The readiness potential was found to precede voluntary acts by about half a second or more (Kornhuber & Deecke, 1965). Kornhuber (1984) discussed the readiness potential in terms of volition, arguing that it is not the manifestation of an attentional processes. Libet discussed it in relation to consciousness and to free will (Libet et al. 1983a; 1983b; Libet, 1985, 1992, 1993). Libet asked the following questions. Are voluntary acts initiated by a conscious decision to act? Are the physiological (...) facts compatible with the belief that free will determines our voluntary acts? What is the role of consciousness in voluntary action? In this paper I will discuss these questions and the answers that Libet gave to them. (shrink)

Libet's experiments, supported by a strict one-to-one identity thesis between brain events and mental events, have prompted the conclusion that physical events precede the mental events to which they correspond. We examine this claim and conclude that it is suspect for several reasons. First, there is a dual assumption that an intention is the kind of thing that causes an action and that can be accurately introspected. Second, there is a real problem with the method of timing the mental events (...) concerned given that Libet himself has found the reports of subjects to be unreliable in this regard. Third, there is a suspect assumption that there are such things as timable and locatable mental and brain events accompanying and causing human behaviour. For all these reasons we reject the claim that physical events are prior to and explain mental events. (shrink)

The problem of free will lies at the heart of modern scientific studies of consciousness. An influential series of experiments by Libet has suggested that conscious intentions arise as a result of brain activity. This contrasts with traditional concepts of free will, in which the mind controls the body. A more recent study by Haggard and Eimer has further examined the relation between intention and brain processes, concluding that conscious awareness of intention is linked to the choice or selection of (...) a specific action, and not to the earliest initiation of action processes. The exchange of views in this paper further explores the relation between conscious intention and brain activity. (shrink)

This is a draft of a paper for a book Philosophy of Action: 5 Questions edited by Jesus Aguilar and Andrei Buckareff and to be published by Automatic Press / VIP. The book contains accounts by various philosophers, including leading theorists, of their engagement with problems of action and agency, and in particular determinism and freedom. The contributors also offer thoughts as to what attracted them to the subject, what their conclusions have been, what the benefit of the subject can (...) be to other subjects, what has been neglected in it, where work and inquiry should now be concentrated, and the prospects for progress. (shrink)

Benjamin Libet and also Libet and collaborators claim to advance a single hypothesis, with important consequences, about the time of a conscious experience in relation to the time when there occurs a certain physical condition in the brain. This condition is spoken of as

_neural_

_adequacy_ for the experience, or, as we can as well say, _neural adequacy_ .5 This finding has been taken to throw doubt on theories that take neural and mental events to be in necessary (...) or lawlike connection, and also certain identity theories of mind and brain, as well as determinist theories. (shrink)

Trevena and Miller provide further evidence that readiness potentials occur in the brain prior to the time that participants claim to have initiated a voluntary movement, a contention originally forwarded by Libet, Gleason, Wright, and Pearl . In their examination of this issue, though, aspects of their data lead them to question whether their measurement of the initiation of a voluntary movement was accurate. The current article addresses this concern by providing a direct analysis of biases in this task. This (...) was done by asking participants to make subjective timing decisions regarding a stimulus that could be measured objectively. Our findings suggest that their timing task was indeed biased such that participants' tend to report events as happening approximately 70 ms later than they actually happened. Implications for the original Libet et al. claims are discussed. (shrink)

Benjamin Libet compared the perceived time of direct brain stimulation to the perceived time of skin stimulation. His results are among the most controversial experiments at the interface between psychology and philosophy. The new element that I bring to this discussion is a reanalysis of Libet's raw data. Libet's original data were difficult to interpret because of the manner in which they were presented in tables. Plotting the data as psychometric functions shows that the observers have great uncertainty about the (...) relative timing of events, as seen the shallow psychometric slopes. A second indication of uncertainty comes from Libet's use of three response categories, A first; B first; and A and B simultaneous. The large number of “perceptually simultaneous” responses provides a further measure of the difficulty of the judgment. There are thus a very broad range of stimulus delays in which the subject is unable to make an accurate ordering response. These points provide evidence that there is no compelling reason to invent exotic or ad hoc mechanisms to account for Libet's data since the uncertainty window is large enough to allow simple mechanism such as memory shifts. Libet argued that his data provide evidence for a backward referral in time. I argue that even though Libet's own data are weak, there are good arguments for a backward referral mechanism to help the subject make sense out of the tangled chaos of asynchronous information associated with experienced events. (shrink)

This issue of Consciousness and Cognition presents four target articles and eight commentaries on the target articles. The present article presents comments on those commentaries, grouped into backward referral and volition categories. Regarding backward referral: I disagree with my fellow commentators and take the unpopular position of defending Libet's notion of backward referral. I join my fellow commentators in critiquing Libet's notion of a 500-ms delay. I examine several of the hypotheses suggested by other commentators for why cortical and lateral (...) meniscus stimulation give very different timing results. I suggest a simple experiment to help discriminate among the hypotheses. I comment on why temporal reordering is more likely to occur late rather than early in mental processing. Regarding Libet's volition experiments, I ask what is the root of the controversy, given the general agreement on the data. I agree with a commentator that Libet's chronotheology rather than his chronoscience is the cause of much of the controversy. Rather than joining others in criticizing Libet for his chronotheology I point out that he is making a respectable philosophical point regarding nondeterministic Free Will, but one that is easily misunderstood. I discuss two ways by which Libet's viewpoint can be brought into mainstream science. (shrink)

S. Pockett and G. Gomes discuss a possible bias in the method by which Libet's subjects estimated the time at which they became aware of their intent to move their hands. The bias, caused by sensory delay processing the clock information, would be sufficient to alter Trevena and Miller's conclusions regarding the timing of the lateralized readiness potential. I show that the flash-lag effect would compensate for that bias. In the last part of my commentary I note that the other (...) target articles do not examine the most interesting aspect of Libet's unfashionable views on free will. I point out that Libet's views are less strange than they at first appear to be. (shrink)

Abstract : Libet’s famous experiments, showing that apparently we become aware of our intention to act only after we have unconsciously formed it, have widely been taken to show that there is no such thing as free will. If we are not conscious of the formation of our intentions, many people think, we do not exercise the right kind of control over them. I argue that the claim this view presupposes, that only consciously initiated actions could be free, places a (...) condition upon freedom of action which it is in principle impossible to fulfil, for reasons that are conceptual and not merely contingent. Exercising this kind of control would require that we control our control system, which would simply cause the same problem to arise at a higher-level or initiate an infinite regress of controllings. If the unconscious initiation of actions, as well as the takings of decisions, is incompatible with control over them, then free will is impossible on conceptual grounds. Thus, Libet’s experiments do not constitute a separate, empirical, challenge to our freedom. (shrink)

The critical reinterpretations of Libet's research by G. Gomes make speculative, unwarranted, and untested assumptions. These assumptions and arguments are analyzed and their status relative to Libet's findings is criticized.

Voluntary acts are preceded by electrophysiological (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event.

Evidence that led to the hypothesis of a backwards referral of conscious sensory experiences in time, and the experimental tests of its predictions, is summarized. Criticisms of the data and the conclusion by Churchland that this hypothesis is untenable are analysed and found to be based upon misconceptions and faulty evaluations of facts and theory. Subjective referral in time violates no neurophysiological principles or data and is compatible with the theory of "mental" and "physical" correspondence.

Sensation elicited by a skin stimulus was subjectively reported to feel stronger when followed by a stimulus to somatosensory cerebral cortex , even when C was delayed by up to 400 ms or more. This expands the potentiality for retroactive effects beyond that previously known as backward masking. It also demonstrates that the content of a sensory experience can be altered by another cerebral input introduced after the sensory signal arrives at the cortex. The long effective S-C intervals support the (...) thesis that a duration of cortical activity of up to 0.5 s is required before awareness of a sensory stimulus is developed. (shrink)